A support is, for example, a shaped plastic part which may be produced, for example, as an injection-moulded part or the like. The intermediate layer which is fastened, for example, adhesively bonded, on and/or over the support may be, in particular, a knitted fabric, namely a knitted spacer fabric.
Weakening in this context means, for example, a weakening of the thickness or a local thickness reduction in the sense of a notch, or else a perforation or the like. A decorative layer, which is made from leather, is as a rule adhesively bonded to the knitted spacer fabric. A shaped trim part which is formed in this way is used, for example, as an interior cover in a vehicle, for example, as a dashboard cover, door interior trim or the like.
In order that an airbag, which is arranged in a firing channel behind the shaped trim part, namely behind the opening cover of the shaped trim part, may trigger reliably, the support is weakened along the opening line with the formation of the opening cover. The opening cover is of substantially rectangular configuration, the weakening as a rule breaking open on three sides during triggering of the airbag, with the result that the opening cover folds open in a hinge-like manner. Here, the opening cover may also include a plurality of covers or cover sections which individually fold open in a hinge-like manner. During the opening, the intermediate layer, for example, the knitted spacer fabric, likewise tears open along the tear line.
In order to avoid the opening cover or airbag cover being visible from the vehicle interior, the entire shaped trim part is as a rule provided with a decorative layer which, for example, is made from leather, without seams or the like being provided in the region of the opening cover. In order to ensure defined tearing open of the airbag cover during the airbag triggering, the leather is split to a maximum thickness of 0.7 mm and used without weakening such as, for example in WO2011038856.
The leather hide may be weakened, with methods of laser weakening being current at the moment. Rear-side weakenings of the leather layer, however, are disadvantageous, since the rear-side weakening lines of the leather layer may stand out on and/or over the surface and may then become visible from the vehicle interior.
German Patent Publication No. DE 10 2006 027 082 A1 discloses a shaped trim part of the type described at the outset, in which the decorative layer is non-weakened in the region of the opening line of the support part or the intermediate layer.
German Patent Publication No. DE 19910141 A1 discloses an airbag covering having a tear line, the covering leather layer having a residual thickness of from 0.3 to 1.5 mm. The weakening is produced by way of a knife, which permits only simple, linear weakening structures. The described region where the residual layer is preserved with a value which begins at 0.3 mm is not suitable for reducing the visibility of the introduction of weakening.
German Patent Publication No. DE 102005013477 discloses a weakening of the covering layer in a curved shape, perpendicularly with respect to the plane of the cover. Here, the residual thickness to be preserved of the cover is considered to be advantageous at from 0.2 to 0.8 mm. This small residual layer may be sufficient in this embodiment, since the different planes of the weakening from the support via the spacer layer and an additional layer are not aligned with the weakening in the actual decorative layer. The production in accordance with this method, however, is very complicated.
German Patent Publication No. DE 19937373A1 discloses a tear edge on a film, no support being provided below the film in this form of interior trim for vehicles. The tear edge is of zigzag-shaped configuration and may be produced via microperforations.